The former deputy prime minister completed a 7.5-hour road trip from Albury on Saturday to open the Canberra Model Rail Expo, where he presented some lucky students with a self-made gauge chart.

Expo manager Andrew Lund said the train lover and author was impressed with the connections between the University of Canberra High School students and the model community, with about 10 students regularly spending time with miniature trains and their owners.

''We've been running the expo here for four years … and we also provide work with the mentoring kids during the week, on a Thursday,'' Mr Lund said.

While Mr Fischer - tipped earlier this year as a leading candidate to be the next NSW governor - was the highest-profile visitor, the little machines were the real drawcard for the thousands to pour into the Kaleen High School, with about 100 running their way around 30-odd separate tracks.

Mr Lund said the event included models of varied scales and time periods, from the 1920s to 1950s Australian trains and Japanese trams.

In addition to an operating railway made of Lego, one track allows children to do their own shunting and compete for the fastest train trip.

The event also brought suppliers to town, with about 20 stalls set up.

''Our first aim is to put on an event that everyone enjoys, and our second aim is for those involved in the hobby, to bring all the specialised providers we want into town,'' Mr Lund said.

The expo continues on Sunday from 9am to 4pm. Entry is $10 for adults, $5 for seniors, children and concession, and $20 for families.